/**
 * Copyright (C) 2007 The AsyncMail Group <asyncmail@googlegroups.com>
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *         http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.googlecode.asyncmail.smtpserver.handler;

import com.googlecode.asyncmail.common.DSNStatus;
import com.googlecode.asyncmail.smtp.SMTPRequest;
import com.googlecode.asyncmail.smtp.SMTPRequestImpl;
import com.googlecode.asyncmail.smtp.SMTPResponse;
import com.googlecode.asyncmail.smtp.SMTPResponseImpl;
import com.googlecode.asyncmail.smtp.SMTPRetCode;
import com.googlecode.asyncmail.smtpserver.SMTPSession;
import com.googlecode.asyncmail.smtpserver.core.CommandHandler;

import java.util.ArrayList;
import java.util.Collection;

/**
 * Handles RSET command
 */
public class RsetCmdHandler implements CommandHandler {
    /**
     * The name of the command handled by the command handler
     */
    private final static String COMMAND_NAME = "RSET";

    /**
     * handles RSET command
     * 
     * @see com.googlecode.asyncmail.smtpserver.core.CommandHandler#onCommand(com.googlecode.asyncmail.smtpserver.SMTPSession,
     *      SMTPRequestImpl)
     */
    public SMTPResponse onCommand(SMTPSession session, SMTPRequest command) {
        return doRSET(session, command.getArgument());
    }

    /**
     * Handler method called upon receipt of a RSET command. Resets
     * message-specific, but not authenticated user, state.
     * 
     * @param session
     *                SMTP session object
     * @param argument
     *                the argument passed in with the command by the SMTP client
     * @return
     */
    private SMTPResponse doRSET(SMTPSession session, String argument) {
        if ((argument == null) || (argument.length() == 0)) {
            session.resetState();
            return new SMTPResponseImpl(SMTPRetCode.MAIL_OK, DSNStatus.getStatus(
                    DSNStatus.SUCCESS, DSNStatus.UNDEFINED_STATUS)
                    + " OK");
        } else {
            return new SMTPResponseImpl(
                    SMTPRetCode.SYNTAX_ERROR_COMMAND_UNRECOGNIZED, DSNStatus
                            .getStatus(DSNStatus.PERMANENT,
                                    DSNStatus.DELIVERY_INVALID_ARG)
                            + " Unexpected argument provided with RSET command");
        }
    }

    /**
     * @see com.googlecode.asyncmail.smtpserver.core.CommandHandler#getImplCommands()
     */
    public Collection<String> getImplCommands() {
        Collection<String> implCommands = new ArrayList<String>();
        implCommands.add(COMMAND_NAME);
        return implCommands;
    }

}
